Train-control system



Dec 11, 192s. 1,694,373 I T. E. CLARK ET AL TRAIN CONTROL SYSTEM Filed Nov; 15, 1926 2 Sheets-Sheet' 1 INVENTORS T6.6M,/.. 61% M4 BY 'W. ti 6 M lvv z m ATTO NEY entree stars Assien'oas o cont nuous Titan; can, a CORPORATION OF MICHIGAN.

ND I AM L. OOOP, or DETROIT-MIO IGAN, CONTROL CORPORATION, OF DETROIT, MICHI- TRAIN-CONTROL sYsTEM.

Application rue'a- November 15, 1926. Serial No. 148,406.

This invention relates to train control systems for railway trains traveling tracks divided into blocks, whereby one or both of tWo radio-frequency currents may be impressed upon the trackrail's at spaced stations in order that electromagnetic force or flux may be picked up from adjacent the rails by receiving coils in the locomotive or other vehicle which is properly provided With air brakes and controlling instrumentalities for such brakes, so that theopef'ation of the vehicle may be governed by such 'radioirequency currents, and its object is to provide transmission instrumental'ities which will impress current of predetermined upon the rails hen the block in advance is unoccupied, which Will impress a current of another When the block in advance is occupied, and which will inipress both of such currents upon the rails of the last block of controlled track so that proper instrumentalities on the locomotive may respond thereto and render the automatic brake-control Inechanisnr inoperative.

A furtherobject of this inventionis to divide each block into cut-sections and to radio-trequency nnpress the same control current upon thev sections of each block so that substantially the same electro-inagnetic fiuX ivill be present along the entire length of such block. 7

This invention maybe embodied in the construction illustrated in the accompanying drawings in which Fig. 1 is a diagram of a trackway installation adapted to impress radio-frequency currents on the rails of the track. Fig. 2 is a diagram of installations designed to be connected to the last section of controlled trackway.

In the draivings, all the ari'na'tures are lettered a and b, and in the following description, these arm'a'tures will be designated by these letters together with the reference numerals of the relays to which each arinature belongs.

The rails in the drawings are shown di-' vided into cut-sections by insulation 3, tree erably at points about one-half mile or 800 meters apart, and these points may be indicated by the half mile markers 4 and mile markers 5. TWO cut-sections constitute a block and a train control station is located at theexit end of each block. Both cut-sections of each block receive the same iadio-fre V quency current, the presence or absence" of" such current depending upon the occupancy of that block and of the occu'pancy 'ot the neat block ahead.

The" instrunientalities embodying the' present inventionare designed to impress a current otone' predetermii'ied vvave length and frequency upon the railsot a block when the block in advance is unoccupied and to impress a current of another shorter Wave length and more rapid frequency u'ponsuch rails when the next block in advance is occupied. l/Vhen a block is tive current passes from the control instrumentalities at the entrance end thereof toward the exit end beyond the vehicle occupying the block,-a11d an othe'r train entering. such block at its entrance end will detect no current in the rails. An- Open switch or broken rail has the same effect; The locomotives to be" operated uponsuch controlled tracks are; induced e'lectroniagnefic fluX or force from the energized rails 3.11am utilize seen force to affect instrunrental-ities to control the operation of the; air brakes and signals thereon, and any desired type of locomotive installation may be employed.

F i'g, 1 diagrammatically illustrates a 'tract installation embodying the pieseint invention and a transmission station of this character provided with means to pick' up quency of the currentloutput of each stav tion is. controlled by euri'ent received over the Wires 7 and 8 from the" next station in advance. A track battery 9 is connected to the rails 1 and 2 at the exit end" of the entrance cut-section A and a" track battery 10 is connected to the entrance end of the rails 11 and 12 of the other out section B. Cur+ rent from battery 9' nor'rnally energizes track relay 14 (not Shows) of the next installation inf the rear while track relay 15 of the control installation of any block is" energized by the battery 10 of that bloclt; Each of these relays are short clrcuited Whenthe cutsection to which it isctn'nected isoeeupi'ed.

The only movable parts of the installation shown in Fig. 1 arena-e armatures of the several relays and they shew iii the solid line positions Whichthey' assume tvhen eat-sections B and G are occupied If secof station E to track relay 14 (not shown) of the next station in the rear and 19,and' 20, armature f in the rear, wire 7 cause its armatures a and b to close that end of the circuit to relay 17. Current would then flow from battery 18 of station B over wires wire 22, control relaylG, wire 7 armature 14 of next station 23 at that s'tation, relay 17 wire 24 armature 14 wire '8 to station B, armature15 and wire 25. This is the.

normal condition of the wayside circuit. lVhcn locomotive enters cut-section A, it

short-fcircuits relay 14 of the installationnext in the rear and causes the circuit of wires 7 and 8 to be opened, resulting in relay 16 of station B to be ,de-energiaed and further resulting, in the dropping of armature 16?,and in the closing of the supply circuit for the generator of high frequency currents at station B.

\Vhen the train leaves section A, the circuit of wires .7 and8 closes behind it but as it enters section B, itshort circuits traclr relay15 of station B which drops its armatures, thus opening the .above described circuitsso tliat control relay 16 cannot again be energized until p the train leaves section B. Relayv 17 atla ny station is therefore de-energized so long as either of the next two cut-sections in advance are occupied; track relay 15 is Clo-energized so lon as the cut-section to which it is connected is occupied; and control relay 16 is Clo-energized so long as either of the, cut-sections of the block in the rear is occupied.

A; C. current preferably of 110 volts, is

supplied to the station from any suitable source by the line wire 27 ,ad' ustably connecting to the primary winding 36 of a transformer 28, and wire 29, armature a'of relay 30 and line wire 31 connect the other end of this winding 36 to the current sourceiRelay 30 receives current from the battery 18 over wires 19 and 32 and connects to the other side of the battery by wires 34 and 33, armature 16 and wire 35, so that so long as control relay 16 is de-energized A. C.

' current will flow to winding 36.

No current flows. to the winding 36 of any station so long'as the block to which the station belongs, 1s unoccup1ed, that is, so.

long as its control relay 16 is energized.

Eachsta-tion embodies two electron tubes, the (oscillations of the output tube 40 being controlled by-those of the master tube 41. As the construction of these tubes is well known, the details need not be described.

The main transformer has three secondary and back over the filament of the blocking condensers 46, winding 44 and 47, and back over wlre 48. The curwire rent for the filament of tube 41 travels-the right-end portion ofwinding 42, connector 45, left-end portion of winding 44, wire 49 wire 50. I

rent of tube 41 travels. from this tube to the plate and thence over wire 52 to a tap on winding 43, while the plate current of tube 40 travels from the filament of that tube to the plate and thence over wire 53 to the end of winding Choke coils 54 are inserted in these wires 52 and 53 to block the radio-frequency oscillations and force them through the condensers 55 and 56 to be explained later on;

The oscillatory circuit which generates the. train control currents is governed by an inductance 57 and condensers between which the wire 60 attaches this wire iitQilClS to the connector 45. A grid leak '61 and choke 62 connect wire 60 to wire 63 which terminates in the grid of the The plate cur tube 41, and also connect to one end of the inductance '57 and to the condenser 58. The other end of the inductance 57 and the condenser 59 connect to'the wire 64 which extends between the condenser 55 and agrid '58 and 59,

condenser 65 and thence through grid leak 66 to the grid of tube40. It will thus be 7 seen that the grid and plate of tube 41 are connected to the ends ofthe inductance and condensers 58 and 59 whereby the tube 41 is caused to produce oscillations of a pre-' determined frequency, this being governed by the inductance 57 and the capacity of the condensers 58 and 59.- a

The plate output of tube 41 being impressed upon the grid of tube 40, the oscillations of tube 40 are governed thereby, and therefore the plate output of this tube 40 is always of the same frequency as that 0 tube 41, and this is unaffected by any connections or conductors which may be attached tothe plate circuitoftube 40. The plate output of tube 40 passes through condenser 56 to primary 68 of the output transformer 69 and thence over wire 67 to wire 60 termini-wingin conductor 45. The grid of tube 40 is unloaded through a leak 70 and choke 71 connecting to wire 67. Practical tests have demonstrated the advisability of using a tube 40 of fifty watts rating and a tube 41 of seven and one-half watts, rating. 7 V

The output transformer i69 has 1 two secondary output windings 7 3 and 74, the

former connecting to the railsll and 12-of cut-section l?) by means of wires 7 5 and 7 (3 and the latter to rails 1 and2 of cut'section A by means of wires 7 '7 and 78. As the length of these wires 7 7 and 7 Sis thelength be separated by of cut-section B, the step-down transformer J9 may be connected into these wires ad-- jacent the rails 1 and 2' so that high-potential current of low amperage may be re ceived from secondary Winding 7 1 and be transformed to low potential and greater amperage at cut-section A, thus permitting the use of small wayside wires.

As stated before, the transformer 69 becomes operative as soon as cut-section A is occupied and this continues until both sections A and B are cleared. As soon as cutsection B is occupied there is no necessity 'of impressing current on rails 1 and 2 of section' A, and a relay 81 is therefore installed to open and close the circuit between the winding 74: and these rails, the circuit to this relay being from battery 18 over wires 19 and 20, armature 15, wire 82' to relay 81 and over wires 83 and 33, armature 16 and wire 35 to the battery. The connection of wire 83 to wire 33 instead of to wire 35 directly is to avoid energizing relay 81 when section A is unoccupied.

In order to change the rate of the oscillating current and of the current impressed upon the rails so as to indicate that the next block in advance is unoccupied, a shunt eircuit consisting of the wire 89 connecting to wire 6A, the armature a of relay 86, and wire 90 connecting to a tap on inductance 57 is employed, the closing of this circuit shortening the inductance and therefore increasing the rate of oscillations of the output current. Relay 86 connects to wire 34 by wire 87 and to wire 20 by wire 88 and armature 17, so that so long as the block in advance is unoccupied and the adjacent relay 17 isenergized, relay 86 will be energized and current of more rapid oscillations will result. But if the block in advance is occupied, relays 17 and 86 will be dc-energized and current of less rapid oscillations will result, and when picked up by the loco-motive through proper instrumentalities caution the engineman to;

reduce speed preparatory to stopping the train at the entrance of the next block.

IVhere a controlled trackway joins onto a trackway which is not provided with control stations, the rails of such trackways may insulation 3 and provisions may be made to simultaneously impress both of the above described radio-frequency currents on the rails of the track section next preceding the noncontrolled trackway, in order that the two currents will so influence instrumentalities on the locomotive that noncontrolled trackway ahead will be indicated. In order to bring the cost of such trackway installations down as low as possible it is advisable to employ two duplicates, as far as may be, of the standard installations shown in F ig. 1. In Fig. 2, the unnecessary parts of installation B are indicated by dotted lines or omitted. In installation C the relay 86 and 96', 82 and 83 is either not While lower frequency oscillations occuryin winding 73 of'installat-ion C. The supply wires 27* and 31 for the main transformer of installation D connect tothe wires 27 and 29 of installation C, the connection between wires 31- and 29 again being erman'ent' as one relay 30 at station 0 is su 'cient.

A battery 9'1 connects to the track rails 1 and 2 of section C by means of wires 95 and normally energizes relay 14 at station B so that until section G always employed. In inby a pin 92 so that only a I y the secondary winding 73 of installation D is occupied relay 16 at installation G is energized by current passing from its battery over wire 8, armature 14; at station B, wire 24, relay 17, wire 23,-armature 1 1 wire 7, relay 16- ofinstallation C, and wires 22and 19. Energized relay 16 holds up its armature a and holds open the circuit of relay 30 until section C is occupied and the installations C and D are inoperative. But-as soon as section C is occupied relay 14 at station B is short circuited resulting in the circuit to relay 16 at installation C being opened and its armature a. dropping to close the circuit to relay 30. Both installations C andD will now become operative to impress both of-the two radio-frequency currents of different wave lengths on the rails of section C.

It will be observed that'these' installations are all biased onthe side of-safety, that is, the breakage or disconnection of any wire or of any tube or other. device employed will result in the interruption of radio-frequency current which will result in' the same lack of such current in the rails as occurs when the block being entered is already occupied.

The cut-sections A and B may be of. any other desired length and the strength of the batteries 9 and 10 will be proportioned accordingly, as will also the several transformers and electron tubes, but such changes as well as changes in the details of construction a are well within the province of radio engineers.

We claim 1. In a train control system, the combina tion of a trackway divided into blocks, each comprising a plurality of sections, a radiofrequency current generator at the eXit end of one block embodying an out ut winding for each track section of said lock, wires connecting said output winding to the exit end of the rails 7 battery connected to one end and a track relay connected to the opposite end of each track section, a control relay having an an of each section, a track for said relay,

frequency currents embodying windings,

vtrack rails divided into "divided into sections, a generator for radio frequency 2. In a train control system, the combination 01'' a trackway divided into blocks, each comprising a plurality of sections", a ra liofrequency current generator and embodying output windings connected to the exit-ends of the several block sections, a control relay adapted to normally hold open the supply circuit for said generator, a current source a track battery connected to one end and a track relay connected to the opposite end oi each track section, and circuit between said current source and said control relay adapted to be closed when either of said trackrelays is short-circuited. A train control system comprising track-rails divided into blocks and the blocks divided into sections, a generator for radioan output transformer including a plurality oi output and wires connecting one of said windings to the rails of each block-section.

LA train control system comprising blocks and the blocks currents embodying an output transformer including a plurality of output windings, and wires connecting one of said windings to the rails of each block-section and means whereby the occupancy of one block-section interrupts the passage of 'current to the section next in the rear.

5. A train; control system comprising track rails divided into blocks and the blocks divided into sections, a generator for radiofrequency currents embodying an output transformer including a plurality or output windings, and wires connecting one of said Windingsto the rails'oi each block-section and means whereby the occupancy of the section at the entrance end of the block causes the transmission of radio-frequency curre t to the rails oithe several. sections o'l': said block, a i

6. A train control system comprising rails divided into blocks the blocks adi means for impressing vided into sections,

two different to the exit end of the controlled'section, aplurality of generators oi radio-frequency currents of different-frequencies connected to the entrance end of the non-controlled section, meansconnected to each section for causin th instrumentalities connected a: thereto to function when such section is oocupied, and means at the generator ,con-

nested to the controlled section and controlled by the instrumentalities connected to the non-controlled section for selecting the frequencies of the current impressed .upon

the rails of the cont olled section. 1 V o 8. A train control system" comprising track rails divided into blocks and the blocks divided into sections, a source of alternating current, means at each block for transforming said current into radio-frequency currents, means connected to a transforming means for one block to impress such currents on the block sections of said block independently of each other, and means responsive to the presence or absence of trains in the block ahead to determine the ireqency of the currents thus impressed.

. THOMAS ECLARK.

JAMES CLARK. WVILLIAM L. COOP.

comprising 

